Gear wheel support

ABSTRACT

A support for a gear wheel, used in a toothed gear change transmission having a shaft and a gear wheel, where the support provides both sufficient axial fixing and radial play between the gear wheel and the shaft, necessary to compensate for working loads. The support is used with a gear wheel having internal teeth with at least one discontinuity in the internal teeth and a groove extending into the internal teeth. The support has a first disc with external teeth and at least one mating discontinuity in the external teeth, whereby the internal and external teeth and the discontinuities, respectively, can coincide with one another. A locking mechanism locks the position of the first disc relative to the gear wheel. To prevent against axial movement of the first disc against the direction of insertion into the groove, the support also includes a securing device.

The invention concerns a support for a gear wheel, preferably for a gearwheel in a toothed gear change transmission.

BACKGROUND OF THE INVENTION

In gear change transmissions gear wheels are used which require an axialfixing but are freely movable radially. Especially in input gear wheelsof such transmissions that are not engaged in the power flow, the fixingin an axial direction and the freedom in a radial direction can beneeded for a working load compensation. The gear wheels can, in thiscase, be provided with a continuous internal profiling. The internalprofile has, in general, a groove in which axial support devices areused.

Also known are gear wheel supports in the toothing of which grooves areprovided in the shaft which allow rotation of a support disc, providedwith an internal toothing, in said groove. Such supports have beendisclosed, for instance, in European patent application 0 390 368. Herethe supporting disc rotated in the groove in the shaft is held in therotated position by a wedge.

The problem to be solved by the invention is to provide a support for agear wheel which makes reliable axial fixing and radial play possible.

BRIEF DESCRIPTION OF THE DRAWINGS

An explanation of the invention is described with reference to thedrawings. In the drawings:

FIG. 1 is a representation of the component parts of the supportaccording to the invention:

FIG. 2 is a representation of the assembled component parts;

FIG. 3 is a partial longitudinal section corresponding to line 3--3 inFIG. 2 from a representation of the arrangement in a transmission;

FIG. 4 is a modified stop disc;

FIG. 5 is the assembled support according to FIG. 4; and

FIG. 6 is the diagrammatic representation of the meshing of teeth.

DETAILED DESCRIPTION OF THE DRAWINGS

In FIG. 1, the component parts of the support are shown. FIG. 1A thusshows the locking disc, FIG. 1B the stop disc and FIG. 1C the gearwheel. It is proposed, according to the invention, to insert a firstdisc 6 in the continuous, internal profiling of a grooved gear wheel 4as stop disc. The internal toothing 8 of the gear wheel 4 has a recess10, in at least one area of its internal diameter, in which at least onetooth of the toothing is not provided. As shown in FIG. 1, preferablythree of said recesses 10 are to be provided. The recesses 10 must bedistributed on the periphery at respectively equal angles.

The first disc 6 has an external toothing 12 which corresponds to theinternal toothing 8 of the gear wheel 4 and which also has on itsexternal toothing at least one recess 14. Said recess 14 is designed sothat at least one tooth of the external toothing 12 is not provided inthis area. Three recesses 14 are also preferably to be provided here.The recesses 14 are distributed on the periphery of the stop disc 6 atequal angles.

The stop disc 6 is inserted in the gear wheel 4, in the internaltoothing 8, up to the groove 30 and rotated in peripheral directionaround at least part of one tooth gap until the teeth of the internaltoothing 8 of the gear wheel 4 coincide with the teeth of the externaltoothing 12 of the stop disc 6. The insertion must be effected in such amanner that the recesses of the internal toothing 8 of the gear wheel 4and the recesses 14 of the external toothing 12 of the stop disc 6coincide. To fix the peripheral direction of the stop disc 6 relative tothe gear wheel 4, and thus avoid a further rotation of the stop disc 6,a second disc is inserted as locking disc 16 likewise in the internaltoothing 8 of the gear wheel 4. Said locking disc 16 has an externaltoothing 18 which likewise corresponds to the internal toothing 8 of thegear wheel 4.

Instead of teeth, at least a so-called "tab" or "knob" is provided as alocking device 22 on at least one area 20 of the external peripherywhich, relative to the plane of the locking disc 16, is bent almost to aright angle. Three such locking devices 22 are also preferably providedhere. Said "tabs" or "knobs" 22 are distributed on the periphery of thelocking disc 16 so as to be adjustable in the recesses 10, 14 of theinternal toothing 8 of the gear wheel 4 and external toothing 12 of thestop disc 6.

If the "knobs" 22 of the locking disc 16 have found their place in therecesses 10, 14 of the stop disc 6 and the internal toothing 8 of thegear wheel, rotation of the stop disc 6 in the groove of the internaltoothing 8 of the gear wheel 4 is no longer possible. The recess 14 ofthe stop disc 6 here can be designed so that over part of the depththereof the tooth shape of the external toothing 12 remains and thelocking device 22 of the locking disc 16 is designed so that saidlocking device extends only into the remaining part of the recess 14.The locking device 22 of the locking disc 16 likewise can be designed sothat the bending relates only to part of the wall thickness of thelocking disc 16 and in the remaining part the tooth shape of theexternal toothing 18 of the locking disc 16 is retained.

The external diameter of stop disc 6 and locking disc 16 is designedsomewhat smaller than the internal diameter of the groove 30 in the gearwheel 4. Therefore, the radial play of the gear wheel 4 is maintained inthe area of the groove 30. The stop disc 6 and locking disc 16 arefreely rotatable on shaft 24.

At least one securing device, such as in the form of a guard ring fixedon the shaft, can be provided against an axial drifting of the lockingdisc 16 toward the shaft that supports the discs 6, 16 and the gearwheel 4.

FIG. 2 shows the three components gear wheel 4, stop disc 6 and lockingdisc 16 in an assembled state. It is to be understood here that therespective teeth of the internal toothing 8, the external toothing 12and the external toothing 18 are superposed and coincide. Likewise themeshing of the locking devices 22 in the recesses 10, 14, 20 is to beseen.

FIG. 3 shows a section from an illustration of the support installed ina transmission. The gear wheel 4, with external toothing 26 and internaltoothing 8 is situated upon a shaft 24. The locking device 22 of thelocking disc 16 extends into the stop disc 6. The locking disc 16 isaxially supported on the shaft 24 by a structural part 28 of thetransmission not specifically designated here.

FIG. 4A shows a modified stop disc for supporting a gear wheel wherebyit is made possible to spare one of said discs in relation to the abovementioned support. For said purpose, the stop disc 6 has a modifiedtooth geometry in which at least one tooth 32 is designed so as to havelonger tooth flanks but not to enlarge the external diameter of the stopdisc 6. This is obtained by the fact that the tooth gaps 34 and 36adjacent the tooth 32 are cut deeper than the remaining tooth gaps. Onlyone tooth 32 is shown in FIG. 4. But three teeth 32 can advantageouslybe distributed on the periphery at equal angles (see FIG. 4B). The toothgaps 34 and 36 are different not only in their depth but also in theirwidth from the tooth gaps 38 of the other toothing. Thus, the spacing ofthe teeth 32 from the adjacent teeth 40 also does not correspond to thespacing from each other of two adjacent teeth 40 and 42. The tooth 32,on the contrary, is disposed so as to be offset, in a peripheraldirection, relative to the other toothing by at least part of its width.

A disc thus shaped can no longer be inserted in the symmetricallydesigned internal toothing of a gear wheel 43. Therefore, the teeth 32,prior to being assembled in the gear wheel 43, are bent at least to theextent that the stop disc 6 can be pushed through the internal diameterof the internal toothing 8 of the gear wheel 43. As soon as the stopdisc 6 is in the groove 30 of the gear wheel 43, the stop disc 6 isrotated in said groove 30 until the teeth 32 coincide with the tooth gapof the internal toothing 8 of the gear wheel 43. The teeth 32 of thestop disc 6 lie, in this position, in tooth gaps of the internaltoothing 8 of the gear wheel 43 while with at least part of their widththe other teeth 40 and 42 of the stop disc 6 coincide with the teeth ofthe internal toothing 8 of the gear wheel 43. An axial displacement ofthe gear wheel 43, relative to the stop disc 6, is now no longerpossible. To prevent further rotation of the stop disc 6 in the grooveof the gear wheel 43, the teeth 32 are bent to an extent such that uponrotation the external tooth flanks of the teeth 32 can come into contactwith the internal tooth flanks of the tooth gaps in which they are.

FIG. 5 shows the assembled state of the gear wheel 43 and of the stopdisc 6. Here, the teeth of the internal toothing 8 of the gear wheel 43coincide in the rotated state of the stop disc 6 with the teeth of theexternal toothing 12 of the stop disc 6. The teeth 32 of the stop disc 6lie in tooth gaps 44 of the gear wheel 43. The axial displacement ofgear wheel 43 and stop disc 6, in relation to each other, is obtained bythe teeth of the internal toothing 8 and the external toothing 12 whilea further rotation of the stop disc 6 is prevented by the teeth 32.

FIG. 6A shows the diagrammatic representation of a gear wheel 43 and ofa stop disc 6 which is situated in a groove 30 of the gear wheel 43.Here the stop disc 6 has the assembled state with amply bent tooth 32while the other teeth 40 and 42 lie in the groove 30.

FIG. 6B shows the diagrammatic representation of a gear wheel 43 and ofa stop disc 6 situated in a groove 30 of the gear wheel 43. The stopdisc 6 has here a final state with reflexed tooth 32 while the otherteeth 40 and 42 lie in the groove 30. The tooth 32 here overlaps withthe internal toothing 8 of the gear wheel 43.

Reference numerals

4 gear wheel

6 stop disc

8 internal toothing

10 recess

12 external toothing

14 recess

16 locking disc

18 external toothing

20 area of the external periphery

22 locking device

24 shaft

28 structural part of the transmission

30 groove

32 tooth

34 tooth gap

36 tooth gap

38 tooth gap

40 tooth

42 tooth

43 gear wheel

44 tooth gap

We claim:
 1. A gear support supporting a gear wheel having a pluralityof internal teeth and a plurality of external teeth;wherein saidinternal teeth (8) of said gear wheel (4) has at least one discontinuityprovided therein; said gear support comprises a first disc having aplurality of external teeth which correspond to said internal teeth (8)of said gear wheel (4), said first disc has at least one matingdiscontinuity formed in said plurality of external teeth which islocated to coincide with said discontinuity of said internal teeth (8)of said gear wheel (4), said external teeth of said first disc areinsertable through said internal teeth (8) of said gear wheel (4) into agroove (30) provided in said gear wheel (4), and said first disc is atleast partially rotatable within said groove (30) whereby coincidence ofsaid internal teeth (8) of said gear wheel (4) and said external teethof said first disc and coincidence of said at least one discontinuity ofsaid internal teeth (8) and said at least one mating discontinuity ofsaid plurality of external teeth is obtainable; and a locking mechanismof said gear support cooperates with said discontinuities, once saiddiscontinuities coincide with one another, to lock the coincidentposition of said gear wheel (4) relative to said first disc.
 2. The gearsupport according to claim 1, wherein said at least one discontinuity insaid internal teeth (8) of said gear wheel (4) is at least one recess(10);said at least one mating discontinuity in the external teeth ofsaid first disc (6) is at least one recess (14); and said lockingmechanism comprises a second disc (16) which has an external toothingthat corresponds to said internal toothing of said gear wheel (4) andsaid second disc (16) supports at least one locking tab (22), saidexternal toothing of said second disc is insertable through saidinternal toothing of said gear wheel (4) into said groove and, once saidteeth and said recesses of said first disc (6) and said gear wheel (4)are coincident with one another, said locking tab (22) is at leastpartially insertable into said recess (14) of said first disc (6) andsaid recess (10) of said gear wheel (4) to prevent relative rotationbetween said gear wheel (4) and said first disc (6).
 3. The gear supportaccording to claim 2, wherein both said first and said second discs havea central through bore by which said first and second discs aresupported on a rotatable shaft to facilitate support of said gear wheel(4) on said shaft.
 4. The gear support according to claim 2, wherein atleast one securing device (28) cooperates with said first and seconddiscs to prevent axial movement of said first and second discs againstthe direction of insertion of said first disc into said groove (30). 5.The gear support according to claim 1, wherein said at least onediscontinuity in said internal teeth (8) of said gear wheel (4) is atleast one tooth gap (44); andsaid at least one mating discontinuity inthe external teeth (12) of the first disc (6) includes at least onetooth (32), located on the periphery of said first disc (6) and offsetin a peripheral direction relative to said external teeth (40, 42), and,after said first disc is inserted through said internal teeth (8) ofsaid gear wheel (4), said locking mechanism comprises moving a flankportion of said at least one tooth (32) into abutment against aninternal flank portion of said tooth gap (44) to prevent relativerotation between said gear wheel (4) and said first disc (6).
 6. Thegear support according to claim 5, wherein said first disc has a centralthrough bore by which said first disc (6) is supported on a rotatableshaft to facilitate support of said gear wheel (4) on said shaft.
 7. Thegear support according to claim 5 wherein at least one securing device(28) cooperates with said first disc to prevent axial movement of saidfirst disc against the direction of insertion of said first disc intosaid groove (30).